INTRODUCTION. 



XI 



Perhaps there is no country in the world where the process of natural selection among birds 

 has had so favourable a field for its operation as New Zealand, owing to its great age as a 

 continental island, and to the entire absence of natural enemies, up to the time, at any rate, 

 of its occupation by man and the introduction of domestic animals which afterwards became 

 feral. As a result, what do we find here as representing the ancient order of Palaeognathic 

 birds? I will not refer at present to the Moa and its kindred, because these birds have become 

 extinct, and, except by way of analogy, do not come into my present subject. But look at the 

 genus Apteryx, taking, for illustration, the oldest known member of the genus, A. australis. 

 Here is a bird with, so to speak, the body of a Turkey and the wings of a Sparrow, these limbs 

 having become so dwarfed by the operation of natural laws that they are reduced to mere 

 rudiments ; yet all the muscular parts, aborted and atrophied though they be, become perfectly 

 distinct under the dissecting knife. Unlike all other known birds, instead of having the nostrils 

 placed in the nasal groove, or on the ridge of the bill (as in the Petrel family), they are situate 

 under a terminal protuberance at the extreme end of the upper mandible ; and, on examination, 

 it is seen that the produced upper mandible is in reality a prolongation of the facial bones — the 

 result, no doubt, of long-continued gradual development in that direction — the brain being pushed 

 back, as it were, into a cranial pan comparatively small for the size of the bird. These modifica- 

 tions of structure are of course adaptations to the feeding habits of the bird, which subsists 

 principally on earthworms, in search of which, aided by its power of smell, it probes the soft 

 ground or loose vegetable mould in its forest haunts. In addition to this the head is furnished 

 with long rictal hairs or feelers, as sensitive as the whiskers of a cat, and its hearing is known to 

 be marvellously acute. 



Mr. Alfred Eussel Wallace, in his admirable work on ' Darwinism,' says (at page 114) : " So 

 soon, however, as we approach the higher and more fully developed groups, we see indications of 

 the often-repeated extinction of lower by higher forms. This is shown by the great gaps that 

 separate the mammalia, birds, reptiles, and fishes from each other ; whilst the lowest forms of 

 each are always few in number and confined to limited areas. Such are the lowest mammals — 

 the Echidna and Ornithorhynchus of Australia ; the lowest birds — the Apteryx of New Zealand 

 and the Cassowaries of the New Guinea region ; while the lowest fish — the Amphioxus or lance- 

 let — is completely isolated, and has apparently survived only by its habit of burrowing in the 

 sand. The great distinctness of the carnivora, ruminants, rodents, whales, bats, and other Orders 

 of Mammalia : of the Accipitres, Pigeons, and Parrots, among birds; and of the beetles, bees, flies, 

 and moths, among insects, all indicate an enormous amount of extinction among the com- 

 paratively low forms by which, on any theory of evolution, these higher and more specialised 

 groups must have been preceded." 



Now, whilst accepting Mr. Wallace's general argument and admitting its soundness, I 

 must venture to differ entirely with that distinguished observer as to the position assigned to 

 the genus Apteryx. I cannot for a moment admit that the Kiwi is one of the lowest birds in the 

 sense implied. It rather seems to me to be an extremely specialised form, and one to which 

 Mr. Wallace's own felicitous remarks (at page 105) are specially applicable : " In species which 

 have a wide range, the struggle for existence will often cause some individuals or groups of 

 individuals to adopt new habits, in order to seize upon vacant places in nature where the 

 struggle is less severe. Some, living amongst extensive marshes, may adopt a more aquatic 

 mode of life ; others, living where forests abound, may become more arboreal. In either case 

 we cannot doubt that the changes of structure needed to adapt them to their new habits 

 would soon be brought about, because we know that variations in all the external organs and 

 all their separate parts are very abundant and are also considerable in amount. That such 

 divergence of character has actually occurred we have some direct evidence." By way of 



